1. Field
Exemplary embodiments of the present invention relate to a method for fabricating a semiconductor device, and more particularly, to a method for fabricating a semiconductor device that has simplified processes.
2. Description of the Related Art
Semiconductor devices may be a memory device to store data. Semiconductor devices may be used to store data in computers, cellular phones, broadcasting devices, education and entertainment devices, and the like.
The circuit area of a semiconductor device is increased in proportion to an increase in memory capacity. However, the area of a memory cell region related to the memory capacity is decreased. Therefore, to secure a designated memory capacity, a larger number of patterns are to be formed in a limited memory cell region, and accordingly, the critical dimension of the pattern becomes fine. To form patterns with a fine critical dimension, a lithography process may be developed.
The lithography process refers to a process of coating a photoresist material on a substrate and forming a photoresist pattern for defining a fine pattern through exposure and development. In the lithography process, a resolution R is determined according to the wavelength λ and numerical aperture (NA) of a light source, i.e., R=k1×λ/NA. In this formula, k1 denotes a process constant. Since k1 has a physical limitation, the value of k1 using a general method may not be decreased. Since a photoresist material having high reactivity for a short wavelength is to be developed together with an exposure device that uses the short wavelength, a fine pattern having a critical dimension less than the short wavelength may be difficult to form. Accordingly, a double patterning technology where patterns are doubly overlapped in consideration of a process ability of the exposure device may be implemented, and fine patterns may be formed without a change in exposure device or exposure condition. Further, a spacer patterning technology may be implemented, which is similar to the double patterning technology but has simplified processes because double exposure and double patterning are not included in the spacer patterning technology. However, since the spacer patterning technology has complicated processes such as a process of forming a photoresist pattern, a process of forming a spacer, and a process of removing the photoresist pattern, these processes are to be improved.